Inkoo and Tahyna, the European California serogroup bunyaviruses: sequence and phylogeny of the S RNA segment

Inkoo (INK) and Tahyna (TAH) viruses, European representatives of the California serogroup (CAL), genus Bunyavirus, family Bunyaviridae, are transmitted by mosquitoes and frequently infect man. The S segments of INK and TAH prototype strains were amplified, cloned and sequenced. INK S consists of 986 and TAH S of 977 nucleotides (nt) coding for a nucleocapsid protein of 235 amino acids (aa) and, in an overlapping reading frame, for a nonstructural protein of 92 or 97 aa, respectively. By S segment sequences and phylogenetic analysis INK was seen to be most closely related to Jamestown Canyon virus, isolated in the USA (92.4% nt and 96.6% aa identity), which is currently classified in a different subcomplex within the CAL viruses. TAH was genetically closest to Lumbo virus, isolated in Mozambique (89.0% nt and 94.1% aa identity). The data suggest that genetic variation within the CAL viruses is less related to geographical distance than to similarity in ecological cycles.